def simple(n):
        d = 0
        for i in range(1, n+1):
            if n % i == 0:
                d += 1
        if d == 2:
            return n
        return 0


digit = ["zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"]
num = input().split()
if len(num) != 3:
    print('Wrong input')
else:    
    if num[0] in digit:
       s = digit.index(num[0])
    if num[1] in digit:
        d = digit.index(num[1])
    if num[2] in digit:
        e = digit.index(num[2])
    n = s *100 + d *10 + e
    print(simple(n))
    